1. Field of the Invention
This invention relates generally to a system which permits use of equipment only during particular times, and more particularly to a system in which the times may be defined only by a person having an authorization device which is recognized by a control system on the equipment.
2. Description of Related Art
The owner of equipment which may be used in his absence, often wishes to control the period of time during which the equipment may be used. For example, to prevent the viewing of objectionable late night television channels by young children. The owner may also wish to have his equipment provided with a disabling device so as to discourage theft of the equipment because it can't be used without having the enabling means.
In the past, a number of timers have been built which allow the operation of equipment for a short period of time, usually a few minutes or hours. However, some of these timers can be reset by an unauthorized person when the time has expired either because no arrangement is provided to prevent this, or because the protective arrangement can be readily thwarted. Other timers require the return of the equipment to the owner to have it enabled for additional time; a requirement which is onerous with some equipment.
U.S. Pat. No. 4,455,093, Bowen et al., entitled: "Timer Mechanism for Rental Equipment", discloses a mechanical timer mounted on rental equipment which limits the time that the rental equipment can be used. A key, retained by the owner, is used to reset the timer, so that the equipment must be returned to the owner in order to get additional time for using the equipment.
U.S. Pat. No. 4,521,843, Pezzolo et al., entitled: "Programmable Wall Switch for Controlling Lighting Times and Loads", discloses an electronic timer which is used to turn a light on or off at times which may be selected. No means for preventing unauthorized resetting of the timer is provided.
U.S. patent application Ser. No. 06/803,218, filed 12/02/85 U.S. Pat. No. 4,624,578, D. Green, entitled: "Rental Contract Timer System", discloses a system where a timer and enabling/disabling equipment are installed on rental equipment. The timer is set by having a card with a magnetic strip encoded with time information. This card is purchased from the renter of the equipment, is read by a decoder on the equipment and is erased at the time it is read.
It is therefore an object of this invention to provide a control system for equipment which requires a properly encoded authorization card in order to use the equipment.
It is also an object of this invention to provide a control system in which an authorized person can set the times during which the equipment can be operated in his absence.
In accordance with these and other objects, which will become apparent hereafter, the instant invention will now be described with reference to the accompanying drawings.